K3 PA bypass in receive

[n6wg]

I've been studying the block diagram of the K3,
and have a question about the 100w PA block.

There is a bypass relay shown in in the PA I/O
block which would provide the receive path.
Is this really a relay or some bypass circuit?
I wouldn't be happy with a relay flapping away, trying
to follow keying.  Hate the clicking noise from
them.

Anybody know?
73, Bob N6WG

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[KK7P]

> There is a bypass relay shown in in the PA I/O
> block which would provide the receive path.
> Is this really a relay or some bypass circuit?

There are no T-R relays, Bob.  The block diagram is indicating a
switching arrangement.  Trust me, the T-R switching is not mechanical at
QRP or QRO levels!

73,

Lyle KK7P

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[N6TR]

On Fri, Sep 21, 2007 at 10:36:24AM -0700, Robert Tellefsen wrote:

> I've been studying the block diagram of the K3,
> and have a question about the 100w PA block.
>
> There is a bypass relay shown in in the PA I/O
> block which would provide the receive path.
> Is this really a relay or some bypass circuit?
> I wouldn't be happy with a relay flapping away, trying
> to follow keying.  Hate the clicking noise from
> them.

I can hear that relay click when you go between low and high power.

It is NOT clicking with QSK.  

Tree
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[Ed Muns, W0YK]

> There is a bypass relay shown in in the PA I/O block which
> would provide the receive path.
> Is this really a relay or some bypass circuit?
> I wouldn't be happy with a relay flapping away, trying to
> follow keying.  Hate the clicking noise from them.

T/R switching is done with semiconductors.  There are no relays "clicking"
with your keying.

73,
Ed - W0YK

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[n6wg]

Thanks, Lyle.
I thought that would be the case, but
good to have it confirmed.

Not ready to operate QRO yet, but when
I buy my K3 it will have the 100w PA in it,
just in case :-)

Thanks and 73
Bob N6WG
The Little Station with Attitude

----- Original Message -----
From: "Lyle Johnson" <[hidden email]>
To: "Elecraft Mail List" <[hidden email]>
Sent: Friday, September 21, 2007 10:47 AM
Subject: Re: [Elecraft] K3 PA bypass in receive

> > There is a bypass relay shown in in the PA I/O
> > block which would provide the receive path.
> > Is this really a relay or some bypass circuit?
>
> There are no T-R relays, Bob.  The block diagram is indicating a
> switching arrangement.  Trust me, the T-R switching is not mechanical at
> QRP or QRO levels!
>
> 73,
>
> Lyle KK7P
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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